This invention relates to synthetic organic continuous filament yarns of mixed filament types and to a process for preparing them.
Yarns composed of different types of filaments are generally known. For example, groups of different colored filaments have been plied together to form a composite yarn as have filaments having different dye affinities. Fabrics prepared from such yarns have a characteristically mottled or blotchy appearance referred to as "heather". Similarly, yarns composed of plied fibers having different luster or shrinkage characteristics have been disclosed in the art.
Various techniques are known for combining mixtures of filaments. These techniques utilize jets, stuffer box crimpers, real twist and false twist methods and the like and combinations thereof. U.S. Pat. No. 3,593,513 issued July 20, 1971 to Reese even describes the production of a yarn by cospinning. A fabric is produced which has a fine heather appearance. The process provides groups of filaments having dissimilar inherent apparent coloration intermingled into a unitary integral yarn as a result of combining the filaments prior to completion of the drawing operation.
However, each of such tecnhiques provides yarns from which fabrics having only a narrow range of mixed filament effects can be produced. One such effect is directionality or streakiness in which the effect of each different filament characteristic is seen flowing into that of the other filament or filaments present. Another such effect is contrast in which the cut-off between the characteristics of each filament type present can range from sharp to ill-defined. In today's marketplace where fashion and styling changes from day to day, it would be advantageous if a single process could be utilized to provide yarns which, in turn, will provide the wide spectrum of mixed filament effects in fabrics, particularly with regard to contrast and directionality.